We know that the way the body grows is by cells dividing. So if a hair is to grow, there must be cell division.
In the immediate vicinity of the dermal papilla there are epidermal cells (called cortical or matrix cells) that are an actively proliferating group of cells. During the growth phase (more about this in a later module) of the follicle, these epidermal cells divide rapidly. The resultant growth is pushed up the follicle and becomes the hair shaft that protrudes above the skin surface, i.e. the part we can see.
Under the influence of the dermal papilla, the epidermal cells differentiates (change) to produce the keratinized hair fibre and associated products. Click here if you want to see that schematic diagram of the hair follicle again.
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This is a microscopic view of the hair papilla. You can click on the image for a larger annotated view. |
